strings vs numbers

[consolacion]

Not really an issue, but more curiosity from my part: You send the humidity as a string with "(String) humidity", however in OpenHab item file you consider it as a number, even as a float with
"Number Humidity "Ambient Humidity [%.0f %%]" {mqtt="<[test:krzychb/home/sensor/Humidity:state:default]"}"
Now obviously that works as I have tried myself, but on other occasions I found openhab rather picky on using a via MQTT received string payload as a number.
Am I missing something ?